@book{2987,
	author = {Hernández Sampieri, Roberto and Baptista Lucio, Pilar, autor.},
	title = {Metodología de la investigación /},
	publisher = {McGraw-Hill, },
	year = {1991},
	address = {México, D. F., México  :},
	edition = {Cuarta edición},
	note = {Incluye índice.}
}